1. Field of the Invention
This invention relates to a truck cover and more particularly to a cover roll assembly rotatably mounted on a headboard of a truck and maintained centered over the open body of the truck as the cover is rolled and unrolled over the open body.
2. Description of the Prior Art
Roll covers for open truck bodies are well known in the art and are disclosed in U.S. Pat. Nos. 3,549,197; 3,549,199; 3,628,826 and 4,341,416. A bail assembly is pivotally mounted on the side walls of the open truck body. A cross bar of the bail is secured to the leading edge of a roll of canvas or tarpaulin and is drawn out from a take-up roll mounted on the cab or headboard of the truck by pivotal movement of the bail assembly from a forward position adjacent the cab to a rearward position adjacent the tailgate. With the bail positioned adjacent the tailgate, the open body of the truck is covered and thus the contents of the truck are covered to prevent spillage from the open body during movement of the truck.
The bail is pivotally mounted outboard of the truck side walls and a dashpot or hydraulic shock absorber exerts a force upon the bail to move the bail to a rearward position. The take-up roll is motor actuated to rotate in a first direction and unroll the cover with a force exerted upon the bail moving it rearwardly to a covered or closed position. One disadvantage with the known arrangements for controlling the movement of the bail as it swings to move the cover between the open and closed positions over the open truck is adjustments in the spring force exerted against the bail. It is important that the force exerted on the bail not be so great as to retard or prevent the cover from being rolled up on the take-up roll. Also, the spring force exerted upon the bail should be sufficient to permit controlled rearward pivotal movement of the bail. The movement of the bail should permit unrestrained unrolling of the cover from the take-up roll while pivoting in a uniform motion to assure that the cover is centered over the open truck body.
Another problem encountered with the known cover roll assemblies is maintaining the cover centered on the take-up roll as it is rolled up on the take-up roll. If the movement of the bail is not controlled during the operation of rolling the cover on the take-up roll, the cover can be displaced from a center position on the take-up roll. As a result, the cover becomes jammed at its edges with the cover housing thereby impeding the unrolling and rolling up of the cover.
Therefore, there is need for a cover roll assembly that is operable to maintain uniform movement of the bail as it is pivoted to cover and uncover the open body of a truck and maintain the cover connected to the bail in a centered position on the take-up roll.